Line trap with demountable tuner



Dec. 25, 1951 M. J. BROWN 2,579,544

LINE TRAP WITH DEMOUNTABLE TUNER Filed Dec. 11, 194

TTT'E TTT WITNESSES: INVENTOR 404 i MyrozgY'j Brown.

ATTORN EY Patented Dec. 25, 1951 2,579,544 .LINE TRAP WITH DEMOUNTABLE TUNER Myron J. Brown, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 11, 1947, Serial No. 791,041

2 Claims.

My invention relates to a carrier-current linetrap which can be tuned from the ground. A

line-trap is essentially a parallel-resonant circuit which is connected in series with a transmission-line conductor as it enters a station, for blocking a carrier-current wave which is used forline-protection, remote-control or metering, communication, or other purposes.

Since the beginning of the use of parallelresonant line-traps, dating back to about 1930, there has been no provision for tuning such units from the ground. Such line-traps are preferably tuned before being lifted'up into position to be connected into the line-circuit; but occasionally it is necessary, due to changed system-conditions, to change the frequency of the carriercurrent wave, and this has heretofore necessitated not only taking the line out of service, but also the hazardous, and often extremely difficult, problem of devising some riggingwhereby a workman may be elevated up to a position where he can work on the line-trap to change its tuning.

The object of my present invention is to provide a line-trap having a demountable tuner, which can be removed with the aid of a hookstick or other insulating handling-means, operatedfrom a distance, by a workman on the ground, (or on some elevated structure), while the line is still in service, using a technique which is in some respects similar to that which has been employed heretofore in the removal of line-fuses, hot-line clamps, and the like.

My invention consists in the parts, structures, combinations, systems, and methods of assembly and use, hereinafter described and claimed, and illustrated in the accompanying drawing, wherein:

Figure 1 is a somewhat idealized longitudinal sectional view of a 150 to 300 kilocycle (kc.) linetrap which employs my invention with a demountable attachment of the entire tuning-unit, including the capacitors and a lightning-arrester, the section-plane being indicated approximately by the lin I-I in Fig. 2,

Fig. 2 is an end View of the'line-trap shown in Fig. 1, V

Fig. 3 is a wiring-diagram of the same linetrap, and

Fig. 4 is a fragmentary, somewhat idealized, longitudinal sectional view of a 50 to 150 kilocycle line-trap which employs my invention with a demountable attachment of only the connection-board for the capacitors.

Asshown in Fig. 1, the main coil of the line- "trap consists of a one-layer winding 5 of strand- 2 ed copper cable, wound on a porcelain spool 6. The porcelain spool 6 is provided with metal endbrackets l and 8, which are connected by strainrods 9 and a strain-insulator I0 in such manner that line-stresses cannot be transmitted to the porcelain spool 6. Each end-bracket I and 8 is provided with a terminal connection I2 (Fig. 2), which receives its end of the coil or winding 5.

There are various ways of mounting a linetrap, the illustrated mounting-means consisting of a set of insulator-supported pipe-elbows I3 and I 4 which are connected to eye-bolts I5 in the respective end-brackets land 8, as shown in Fig. 1.

In the form of my invention which is shown in Fig. 1, the line-trap is provided with an externally mounted tuning unit I6, which is shown at the left-hand end of the coil. This tuningunit I6 has a porcelain housing I1 to which metal back (or bottom) and front (or top) covers I8 and I9 are secured. The unit I6 contains a plurality of diagrammatically indicated capacitors 2|, of assorted sizes, which are connected between a common bus 22 and a, plurality of individual screw-hole terminals 23 which are spaced immediately below a set of corresponding screw-holes 24 in the front cover l9, so that connection can be made from the front cover I9 to any capacitor or capacitors 2| by means of one or more screws 25, as diagrammatically indicated in Fig. 1. The common capacitor-bus 22 is connected to the back (or bottom) cover I8 through a conductor 26. The unit I6 also contains a lightning-arrester 2! which is connected between the front and back covers I8 and I9.

In accordance with my invention, the tuningunit It is demountably mounted on the endbracket I of the coil-structure by any means which is susceptible of manipulation through an insulating manipulation-means which is operable from a distance while the line is charged. In the form of construction which is shown in Fig. 1, and which is preferred when th capacitor-unit or structure is light enough to be conveniently handled, the demountable mounting of the capacitor-unit, 0r tuning-unit, I6, is achieved by means of lower and upper metal brackets 28 and 29, which are carried by the respective end-plates or covers I8 and I9 of the tuning-unit l6.

Cooperating with the upper bracket 29 of the. tuning-unit I5 is a metal supporting-bracket 3| which is carried by the end-bracket Tat that end of the coil-structure. The supportingbracket 3I may conveniently be secured to the end-bracket l by the same nuts 32 which engage the ends of the strain-rods 9. The supportingdisengaged from its post 39.

bracket 3| has an outwardly bent top portion 33 which terminates in a hook 34 which extends through an elongated slot 35 (Fig. 2) in the upper bracket 29 of the tuning-unit. The supporting-bracket 3! also has an outwardly extending metal post 36 which is welded thereto, and the end of the post 36 abuts against the back of the upper tuning-unit bracket .29 at a point spaced from the hook-receiving slot 35. A demountable electrical and mechanical connection may be provided, between the upper tuning-unit bracketZQ and the post 36, by means of a ringbolt 37"which is trapped by a trapping-bracket 38 carried by the upper tuning-unit bracket 29,, so that the ring-bolt cannot become lost when it is disengaged from the end of the post 36 V The lower bracket 28 of the tuning-unit l6 abuts against the end of another metal post 39. which is shown as extending outwardly from an insulating plate 4! which lies back of the end- .bracketfi .at that end-of the coil-structure. This insulatingplate 41 may convenientlybe secured byni ts 43-011 the strain-rods 9. The inner end of the post 39 is connected, by a conductor 43, to the other end-bracket B, at thefar end of the ooil-structure, so that it is electricallyconnected to the far end of the coil or winding 5.. A demountabl-e electrical and mechanical connection maybe provided, between the lower tuning-unit bracketiiii and the post 39, by means of another trapped ring bolt 47 which is carried by the bracket 28.. I

The upper bracket 29 of the tuning-unit I6 terminates, at its top, in a ring having an opening of substantially the same size as the openings in the rings of the ring-bolts 3'! and 4?.

End-traps or cover-plates 58 are commonly provided at each end of the line-trap.

In the operation of the demountahle tuningmeans which is shown in Figs. 1, 2 and 3, it will be understood that the coil 5 of the line-trap is electrically connected in series with a line-conductor L, L,. as shown in Fig. 3, but physically the line-trap may be disposed in any position, horizontal, vertical, or inclined, but preferably with the tuning-unit end of the line-trap disposed. so that it is most conveniently. accessible ior dismounting. The terms upper and lower, as her inabove used, are therefore only convenient reference-terms, applicable to the particular mounting chosen for illustration, and not'intended to indicate any limitation in the direction of mountng.

To dismount my tuning-element while the line L is in service, it is convenient to use a hook-stick 50, which is shown in Fig. 1. A hook-stick, as already developed in the art, for somewhat similar hot-wire work, consists of a long wooden pole 61, having some kind of a headed pin 62 on its end. To remove the tuning-unit 16 from the line -trap of Fig. 1, the hook-stick pin 52 is first 4 the line-trap shall be provided with a tuningelement which is physically and electrically dis engageable therefrom, by an insulating manipulating-means, so that the tuning-element can be removed, retuned, and restored to its original place'when the line-trap is in either a horizontal or vertical plane. The line-trap which-is shown in Figs. 1, 2 and 3, was designed forthe higher range of carrier-current frequencies, so that its entire capacitor-unit, or tuning-unit, l6, 7 was light enough to be conveniently lifted down, with a hook-stick 6B, and this procedure was preferred, for such a line-trap, because it entailed the use of only two dernountable electrical connections, at the ring-bolts 3! and '31 respectively.

Fig. 4., however, diagrammatically indicates a line-trap which is designed for the lower range of carrier-current frequencies. Here, the capac- 1 itors II are so large that they have to be'mounted inside of the porcelain spool Got the main coil '5, and these capacitors are too heavy vfor practical handling at the end of a hook-stick. In Fig. 4, however, the assorted-size capacitors H are electrically connected'tobusses of a cross- .bussed tuning-element 12, of a particular type which is described and claimed in my copending application. Serial No. 751,069, filed May 28, 1947, .now Patent No. 2,467,727. 113' is Sufficient to say, here, that the tuning-element 12 is'the' means whereby the capacitors H may be connected in many different combinations of par?- allel, series, and series-parallel arrangements, 'for tuning the line-trap to different carrier-current frequencies. In accordance with my invention, as diagrammatically indicated in Fig. 4,, the tuning-element 72 is put on the removable part of a two-part electric plug-connector 755, having as many poles as may be needed, preferably a separate pole for each of the terminals of the plurality of capacitors-ll and the coil 5. The tuning-element 1-2 is normally held in place by a frictional connection, or by any other demountable connection; and it is provided with a demounting loop 1.!

which can be engaged by a hook-stick so that the of service.

inserted in the upper ring-bolt 3], as shown in Fig. l, and thisring.bolt is screwed out of engagement with its post 35, by twisting the hookstick. Then the lower ring-bolt 41 is similarly Finally, the hookstick pin 62 is engaged-with the top ring '51 of the upper tuning-unit bracket 29, and the tuningunit Hi can be disengaged from the hook 34 and lifted down, where it can be retuned, by suitable i manipulation of the connection-screws 25 in the front '(or bottom) cover 58 0f the unit, after which the unit may be replaced by a reversal of the dismounting procedure.

essential feature of my invention is that While I have illustrated only two exemplary forms of embodiment of .my invention, and while I have illustrated certain exemplary forms of disengagea'ble electrical and mechanical connections, adjustable tuning-arrangements, and insulating remote-control manipulating-means, I Wish it to be understood that my invention is not altogether limited to such details, as various changes may be made by way of additionsomissions, and the substitution of equivalents. Idesire, therefore, that the appended claims shall be accorded the broadest construction consistent with their language.

I claim as my invention: a

' 1. A line-trap comprising a main-coil structure and a demountable tuning-unit, said maincoil structure comprising acoil, terminal coilbrackets which are electrically connected tojthe respective coil-ends, a demouhtable supportingmeansat one end of said main-coil structure, said demountable supporting-means comprising two conducting seating-structures, one electr-ically connected to the adjacent coil-bracket,

of capacitors of assorted sizes, a capacitor terminal-board means whereby a, plurality of different capacitors and capacitor-combinations may be connected, and two mounting-bracket elements for opposite terminals of said tuningunit, said mounting-bracket elements having distance-manipulable mounting-means for engaging the respective seating-structures.

2. The invention as defined in claim 1, characterized by said demountable supporting-means also comprising a hooked supporting-bracket, and said tuning-unit also having a bracketmeans having an elongated slot engageable by the hooked supporting-bracket, said tuning-unit also having a distance-manipulable liftingmeans for handling the unit when said mounting-means are disengaged from their seatingstructures.

MYRON J. BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,260,163 Brown Oct. 21, 1941 2,260,164 Brown et al. Oct. 21, 1941 2,278,371 Guy Mar. 31, 1942 2,348,034 Stotenbur May 2, 1944 FOREIGN PATENTS Number Country Date Germany Nov. 5, 1936 

